I'd say it almost definitely will post as 1 segment, though humanoid94's experience may prove otherwise. But, a TTU after the flights post to your account explaining that you booked the flight as a connection (and paid the add'l fees that go with it), a schedule change made it a direct flight, and that change will result in your inability to retain status. Then kindly request credit for the original ticketed and paid itinerary (and your argument can be bolstered more if/when you get stuck with an "unscheduled" aircraft change in DTW).